EEschema: The background of the pages is always plotted

Description

The background of the pages is always plotted, this is a big problem especially with black and white printing.

Steps to reproduce

vokoscreen-2020-07-26_22-32-41

KiCad Version

Application: Eeschema

Version: 5.99.0-unknown-bf445c1~102~ubuntu18.04.1, release build

Libraries:
	wxWidgets 3.0.4

Platform: Linux 5.3.0-62-generic x86_64, 64 bit, Little endian, wxGTK

	wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.22
	Boost: 1.65.1
	OCE: 6.9.1
	Curl: 7.58.0
	ngspice: 32+
	Compiler: GCC 7.5.0 with C++ ABI 1011

Build settings:
	KICAD_SCRIPTING=ON
	KICAD_SCRIPTING_MODULES=ON
	KICAD_SCRIPTING_PYTHON3=ON
	KICAD_SCRIPTING_WXPYTHON=ON
	KICAD_SCRIPTING_WXPYTHON_PHOENIX=ON
	KICAD_SCRIPTING_ACTION_MENU=ON
	BUILD_GITHUB_PLUGIN=ON
	KICAD_USE_OCE=ON
	KICAD_SPICE=ON